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TX Ursae Majoris
	; A light curve for TX Ursae Majoris, plotted from TESS data
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Ursa Major
Right ascension	10h 45m 20.504s
Declination	+45° 33′ 58.71″
Apparent magnitude (V)	6.97
Characteristics
Spectral type	B8V + G0III-IV
B−V color index	−0.003±0.026
Variable type	β Per
Astrometry
Radial velocity (Rv)	−13.2±0.9 km/s
Proper motion (μ)	RA: 9.595 mas/yr ; Dec.: 4.412 mas/yr
Parallax (π)	4.1849 ± 0.0841 mas
Distance	780 ± 20 ly ; (239 ± 5 pc)
Absolute magnitude (MV)	0.60
Orbit (1990)
Period (P)	3.063 d
Semi-major axis (a)	≥ 3.315 R☉
Eccentricity (e)	0.0134
Argument of periastron (ω); (secondary)	324.7°
Semi-amplitude (K1); (primary)	54.8 km/s
Details
TX UMa A
Mass	4.76±0.16 M☉
Radius	2.83 R☉
Luminosity	182+18; −16 L☉
Surface gravity (log g)	4.2±0.15 cgs
Temperature	12,900±300 K
Rotational velocity (v sin i)	69±3 km/s
TX UMa B
Mass	1.18±0.06 M☉
Radius	4.24 R☉
Luminosity	13.5+6.0; −4.2 L☉
Surface gravity (log g)	3.3±0.3 cgs
Temperature	5,500±500 K
Rotational velocity (v sin i)	72±5 km/s
Other designations
	TX Uma, BD+46 1659, GC 14783, HD 93033, HIP 52599, SAO 43460, PPM 52052
Database references
SIMBAD	data

TX Ursae Majoris is an eclipsing binary star system in the northern circumpolar constellation of Ursa Major. With a combined apparent visual magnitude of 6.97,^[3] the system is too faint to be readily viewed with the naked eye. The pair orbit each other with a period of 3.063 days in a circular orbit,^[7] with their orbital plane aligned close to the line of sight from the Earth. During the primary eclipse, the net brightness decreases by 1.74 magnitudes, while the secondary eclipse results in a drop of just 0.07 magnitude.^[5] TX UMa is located at a distance of approximately 780 light years from the Sun based on parallax measurements,^[2] but is drifting closer with a mean radial velocity of −13 km/s.^[6]

In 1931, H. Rügemer and H. Schneller independently discovered this is an eclipsing binary system of the Algol type.^[11] Rügemer later found that the eclipse period was not constant,^[12] a behavior that was subsequently explained as apsidal precession.^[13] B. Cester and associates in 1977 confirmed this is a semidetached binary system consisting of a main sequence primary star and an evolved giant companion.^[14] A study of the system by J. M. Kreiner and J. Tremko in 1980 disproved that changes in the eclipse period are due to apsidal motion.^[12]

The light curve of this system shows little impact from proximity effects between the two stars, making it only weakly interacting. The primary eclipse is very deep with less than 5% of the brighter star's light appearing at central eclipse,^[15] allowing the spectrum of the fainter secondary to be directly examined.^[16] In addition to a steady decrease in the system orbital period, multiple irregular changes in the period were observed between 1903 and 1996.^[17] The slowing orbit may be due in part from magnetic breaking of the mass-donor secondary, causing a transfer of angular momentum to the system. An accretion disk may be a contributing factor.^[18] Spectral evidence supports an accretion disk in orbit around the primary that is sustained by mass transfer.^[19] A faint emission from the system is evidence of a circumbinary ionized shell.^[20]

The cooler secondary component is the more evolved member of the pair with a stellar classification of G0III-I,^[4] having previously exhausted the supply of hydrogen at its core and evolved off the main sequence. This star has filled its Roche lobe and is contributing mass to the primary.^[8] It now has 1.2 times the Sun's mass but has expanded to 4.2 times the solar radius.^[8] The secondary is rotating synchronously with its orbit.^[8] The primary component of this system is a B-type main-sequence star with a stellar classification of B8V.^[4] It is rotating 1.5^[8] times as fast as the orbital rate due to the impact of mass accretion from the secondary.^[4] The primary has 4.8 times the mass and 2.8 times the radius of the Sun.^[8]

References

^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
^ ^a ^b ^c ^d ^e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
^ ^a ^b ^c ^d Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
^ ^a ^b ^c ^d Komžík, R.; et al. (June 2008), "Asynchronous rotation of the mass gaining component in the Algol-type binary TX UMa", Contributions of the Astronomical Observatory Skalnaté Pleso, 38 (3): 538–544, Bibcode:2008CoSka..38..538K.
^ ^a ^b Samus', N. N; et al. (2017), "General catalogue of variable stars", Astronomy Reports, GCVS 5.1, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
^ ^a ^b Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
^ ^a ^b Hric, Ladislav; et al. (July 1990), "Spectral Behaviour of the Eclipsing Binary Tx-Ursae around Primary Minimum", Astrophysics and Space Science, 169 (1–2): 241–243, Bibcode:1990Ap&SS.169..241H, doi:10.1007/BF00640723, S2CID 122156362.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o Glazunova, L. V.; et al. (August 2011), "TX UMa: new orbit, spin rotation and chemical composition of components", Monthly Notices of the Royal Astronomical Society, 415 (3): 2238–2244, Bibcode:2011MNRAS.415.2238G, doi:10.1111/j.1365-2966.2011.18854.x, S2CID 13387816.
^ ^a ^b Malkov, Oleg Yu (February 2020), "Semidetached double-lined eclipsing binaries: Stellar parameters and rare classes", Monthly Notices of the Royal Astronomical Society, 491 (4): 5489–5497, Bibcode:2020MNRAS.491.5489M, doi:10.1093/mnras/stz3363.
^ "TX UMa", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-02-25.
^ Komzik, R.; et al. (December 1992), "Spectroscopic and Photometric Detection of Interacting Processes and Their Evolution in the Eclipsing Binary Tx-Ursae", Astrophysics and Space Science, 198 (1): 149–159, Bibcode:1992Ap&SS.198..149K, doi:10.1007/BF00644309, S2CID 123353083.
^ ^a ^b Kreiner, J. M.; Tremko, J. (1980), "Analysis of the Change of Period and the Photometry of the Minima of the Eclipsing Binary System TX Ursae Maioris", Bulletin of the Astronomical Institute of Czechoslovakia, 31: 343, Bibcode:1980BAICz..31..343K.
^ Plavec, M. (1960), "Influence of precession and nutation on the period of eclipsing variables", Bulletin of the Astronomical Institute of Czechoslovakia, 11: 197, Bibcode:1960BAICz..11..197P.
^ Cester, B.; et al. (November 1977), "Revised photometric elements of 12 semi-detached systems", Astronomy and Astrophysics, 61: 469–475, Bibcode:1977A&A....61..469C.
^ Hill, Graham; Hutchings, J. B. (January 1973), "The Synthesis of Close-Binary Light Curves IV. An Application to TX Ursae Majoris and MR Cygni", Astrophysics and Space Science, 20 (1): 123–148, Bibcode:1973Ap&SS..20..123H, doi:10.1007/BF00645591, S2CID 119821890.
^ Grygar, J.; et al. (November 1991), "Direct Detection of the Secondary Spectrum of the Interacting Eclipsing Binary Tx-Ursae", Astrophysics and Space Science, 185 (2): 189–193, Bibcode:1991Ap&SS.185..189G, doi:10.1007/BF00643187, S2CID 120589676.
^ Qian, Shengbang (November 2001), "Possible Mass and Angular Momentum Loss in Algol-Type Binaries. V. RT Persei and TX Ursae Majoris", The Astronomical Journal, 122 (5): 2686–2691, Bibcode:2001AJ....122.2686Q, doi:10.1086/323455, S2CID 121698690.
^ Chen, Wen-Cong; et al. (October 2006), "Orbital Evolution of Algol Binaries with a Circumbinary Disk", The Astrophysical Journal, 649 (2): 973–978, arXiv:astro-ph/0606081, Bibcode:2006ApJ...649..973C, doi:10.1086/506433, S2CID 13973276
^ Iliev, L. (December 2010), Prša, Andrej; Zejda, Miloslav (eds.), "Spectral Evidence of Circumstellar Material in the Eclipsing Binary TX UMa", Binaries - Key to Comprehension of the Universe. Proceedings of a conference held June 8-12, 2009 in Brno, Czech Republic, vol. 435, San Francisco: Astronomical Society of the Pacific, p. 345, Bibcode:2010ASPC..435..345I.
^ Taranova, O. G.; Shenavrin, V. I. (November 1997), "Search for dust shells in W Ser binaries and similar object: RX Cassiopeiae and TX Ursae Majoris", Astronomy Letters, 23 (6): 698–703, Bibcode:1997AstL...23..698T.